||MOLECULAR DETECTION OF t(14;18). Lymphomas have been associated with a particular cytogenetic aberration, wherein the BCL-2 gene on chromosome 18 is translocated to one of the immunoglobulin heavy chain (JH) regions on chromosome 14. This brings the BCL-2 gene under IgH gene regulation and results in over-expression of the anti-apoptotic BCL-2 protein. This multiplex, nested PCR method employs primers for two breakpoint cluster regions--the major (MBR) and the minor (mcr). Detection of this translocation can be useful both diagnostically and in assessing residual disease following therapy.